NEW DELHI Another gunman was confirmed killed on Sunday in an operation to clear the Pathankot air base after a militant attack, a home ministry source told Reuters, bringing the total number of assailants eliminated to six.

"The decision to blow up the one of the administrative units was taken to neutralise the sixth militant. It was also needed to makes sure we destroy live grenades," the source told Reuters on condition of anonymity.

The source said it was not yet clear whether the air base was now fully secured but efforts were under way to complete the operation before nightfall.

At least six Indian military personnel have died since gunmen launched an audacious pre-dawn attack on Saturday on the Indian Air Force Base at Pathankot, just 25 km from the border with Pakistan.